Removal of unused audio drivers

[Maarten Lankhorst]

There are 5 different audio drivers for linux, I think this is a bit
overkill, so I propose to remove the esd and nas drivers, I don't think
anyone uses esd, especially that since for that task alsa can be used
now since dmix addon.

I'm not sure what nas is for, but it seems to be 'network audio system',
I haven't seen any use for it, except that it causes a 30 seconds
slowdown at showing 'audio' tab in winecfg. I don't think anyone uses it.

For esd I think it's best to remove, for nas I'm also for remove, but
I'll settle for removing it from winecfg list same way as winearts was
disabled for a while.

What are your thoughts about this?

Maarten